Dental tool



' Feb. 27, 1923.

Filed Mar. 18, 1921 Invenior William A. Kelsey Patented Feb. 27, 1923.

W I M A KE'LS'E'Y; D MiiX NEA bI IS, anima e.

DElY T i OO Application filed March 18, 1921-. Serial No. 453,212

To all whom it may concern Be it known that I, iVILLIAM A. KnLsnY, a citizen of the United States, resident of Minneapolis, in the county of Hennepin and State of Minnesota, have invented certain new and useful Improvements in Dental Tools, of which the following is a'specification.

This invention relates to improvements in dent-a1 tools of the type usually employed in pyorrhoea work where it is necessary to thrust the working edge of the instrument between the teeth and down to the roots thereof for the purpose of cleaning the surfaces of the teeth. In this work the operator cannot see the edge of the implement and cannot tell the exact position of the cutting edge with respect to the surface on which he is working.

It is the object of my present invention to provide a dental tool that will automatically square or seat itself on the surface to which the cutting edge is applied.

The invention consists generally ina dental tool constructed as hereinafter specified and pointed out in the claims.

In the accompanying drawings forming part of this specification,

Figure 1- is a view illustrating my improved tool in use, showing the position of the hand of the operator thereon,

Figure 2 is a similar view of the tool, with the hand removed, indicating the working axis and the axis of the handle part of the tool,

Figure 3 is a plan view looking down upon the top of the tool shown in Figure 2.

In the drawing, 1 represents the handle or hand grip portion of the tool. Formed integrally with the handle of the tool is a shank portion 2, a part of which, between the points 3, 3, may properly be designated the finger rest or pressure applying portion of the tool. This portion of the tool has its axis extending at an angle to the axis of the handle; is preferably substantially circular in cross section and tapering slightly in diameter, and is provided with a series of circular grooves 4, which prevent forward or backward slipping of the tool in the hand while presenting no resistance to a turning or circular movement of the tool. 5 designates the end portion of the shank of the tool, provided with a cutting edge 6. The part 5 of the shank may be curved or bent into any preferred shape to adapt it to the be given to the part 5 of'the shank.

particular work for which the tool is to be used, The pressure portion of the shank of the tool, extending between the points 3, 3, having its axis at an angle to the axis of the handle portion 2, is preferably arranged in relationto the cuttiii'g'edge 6, so that a line coincident with the u per surface of said pressure portion extends througl-i the cutting edge 6, and extended in the opposite direction passes through the handle portion of the tool and emerges at substantially the point 7, which may be designated the fulcrum of the tool.

The result is that when the tool is in use and is held in the hand of the operator, substantially as shown in Figure 1 of the drawings, the cutting edge, or work point 6, the upper surface of the pressure portion 3, 3, of the shank, and the fulcrum 7, or point of resistance of the tool upon the hand, are all in the same straight line. When the operator holds the tool in his hand, substantially as illustrated in Figure 1 of the drawing, and applies pressure to any part of the surface between the lines 3, 8, if the cutting edge is not squarely seated upon the surface to be operated upon, the tool will automatically turn in the operators hand and bring iaid cutting edge squarely upon said surace.

A large number of different shapes mpy 11 every instance, however," the cutting edge will be so located that astraight line coincident with the upper surface of the finger rest or pressure applying portion of the tool, if extended, willintersect said cutting edge.

I claim as myinventionr 1. A dental tool, comprising, in combination, a handle or hand grip portion, with a shank projecting from its end at an angle thereto, the part of the upper surface of the shank that is contiguous to the end of the handle forming a pressure surface, and the end of the shank having a cutting edge, the extension of a straight line coincident with said pressure surface intersecting said cutting edge.

2. A dental tool, comprising, in combination, a handle or'hand grip portion, with a shank projecting from its end at an angle thereto, said shank being provided at its end with a cutting edge, and the portion of the shankthat is contiguous to the end of the'handle being provided with a series of circumferential grooves.

so i

3. A dental tool, comprising, in combination, a handle or hand grip portion, with a shank projecting from its end at an angle thereto, the end of the shank being turned inward toward the axial line of the handle, and provided with a cutting edge, and ar-. ranged in relation to said shank, so that a straight line, coinciding with the upper surface of the shank, extended will intersect said cutting edge.

d. A dentaltool, comprising, in combination, a handle or hand grip portion, with a shank projectingfrorn its end at an angle thereto, the upper part of the surface of the shank that is contiguous to the end of the handle forming a pressure surface, the end of the shank being turned inward toward the axial line of the handle and provided with a cutting,- edge, so arranged in relation to said shank, that the extension of a straight line coincident with said pressure surface intersects said cutting edge.

5. A dental tool, comprising, in combina tion, a handle or hand grip portion with a shank prO 'ectmg Ironi its end an angle thereto, the part of the upper surface of the shank that is contiguous to the end of the handle forming a pressure surface and being provided wlth a series of circumferential grooves, the end of the shank having a cutting edge and the. extension of a straight 

